1. Technical Field
The present invention relates to a thermal stencil making unit that makes a stencil of a perforated image on a thermal gauze by a thermal print head while relatively moving the thermal gauze tightly stretched in a gauze frame and the thermal print head, and that includes a head protecting member for protecting the thermal print head when the gauze frame is set.
2. Related Art
Generally, because of having a simple structure and allowing a simple stencil making operation, there is widely used a thermal stencil making unit that makes a screen stencil by heating and perforating image information in a heat-sensitive film of a thermal gauze through the use of a plurality of heat elements provided in the thermal print head by relatively moving: the thermal gauze in which the thermal film is stuck with an adhesive agent onto the gauze tightly stretched in the gauze frame and having a plurality of meshes by weaving warps and woofs; and the thermal print head having, on its surface, a plurality of the heat elements for heating and perforating this thermal gauze.
In addition, an image is screen-printed on a sheet or a T-shirt by dropping ink onto the screen plate on which a stencil is made by the thermal stencil making unit.
As an example of this type of the thermal stencil making unit, there is known a thermal stencil making unit using a thermal print head in which a surface portion of the thermal print head can be protected by a head protective plate when the gauze frame is replaced (for example, refer to Patent Document 1).
In the thermal stencil making unit using the thermal print head disclosed in Patent Document 1, the gauze frame in which the thermal gauze is tightly stretched is detachably fixed to a stencil making unit body, although not shown here.
Furthermore, a platen roller is provided below the thermal gauze in the stencil making unit body. On the other hand, above the stencil making unit body, a thermal print head portion in which the thermal print head is mounted on a thermal print head supporting member is openably and closably mounted above the thermal gauze.
At this time, the platen roller and the thermal print head portion are movably provided by being guided by a pair of guide rails.
In addition, when a stencil is made, the platen roller and the thermal print head are moved while the thermal gauze is sandwiched between the platen roller and the thermal print head in a pressure-contact manner, and thereby a stencil of the perforated image is made on the thermal gauze.
Furthermore, a pair of plate supporting members that support the head protective plate for protecting the surface portion of the thermal print head are rotatably mounted on the thermal print head supporting member of the thermal print head portion.
The pair of these plate supporting members also have a function as an operation lever of the head protective plate and is constituted so as to selectively open/close the surface portion of the thermal print head by rotating the head protective plate via the pair of plate supporting members.
With the configuration described above, when the thermal print head is to be used with the thermal print head portion being closed, the head protective plate is rotated in an opening direction and is separated from the surface portion of the thermal print head. On the other hand, it is described that when the thermal print head portion is opened for replacement of the gauze frame, the head protective plate is rotated in a closing direction to thereby protect the surface portion of the thermal print head, whereby damage on the thermal print head can be prevented.